Antifungal T-cell responses of neonates, infants, and children

新生儿、婴儿和儿童的获得性免疫反应与成人不同。事实上，在生命的早期阶段，CD4+T细胞的激活和分化高度依赖于年龄。然而，到目前为止，这主要是通过抗原非特异性多克隆刺激来证明的。新的初步结果现在表明，即使是抗原特异性反应--作为一个模型，抗真菌T细胞对白色念珠菌或烟曲霉菌的多肽和裂解产物的反应--也是从出生起就强烈启动的。新生儿反应性T细胞池由20个不同的TCRVβ家族组成，而儿科和成人T细胞池的变异性明显较小。我们不能表现出IL-4表达的年龄依赖性，但有明显的IL-17和IL-10的产生。值得注意的是，只有新生儿和婴儿的T细胞显示出多种细胞因子的即时共表达。此外，只有他们幼稚的、激活的T细胞共表达转录因子T-bet和RoRγt，随后表达它们的靶基因IL-17和干扰素γ。这表明新生儿和婴儿的T细胞对真菌的高度可塑性是预先确定的，这可能为治疗干预提供一个干预点。在本项目中，我们将以我们在人类T细胞中对白色念珠菌和烟曲霉的抗真菌反应为模型，重点研究与年龄相关的抗原特异性T细胞激活和分化的功能和分子方面。首先，我们将把我们最初关于多克隆、非抗原特异性T细胞激活的工作扩展到抗原特异性，使用MELC技术来分析T细胞APC突触。接下来，我们将使用细胞因子信号传递、STAT分析和T细胞分化方法，使用细胞分裂谱来鉴定新生儿型IL-17的产生及其可塑性。另一个目标是对新生儿、婴儿和儿童中的抗真菌IL-10产生进行功能和分子分析，我们将其视为关闭T细胞反应(包括Th17)的关键开关。为此目的，将进行分化试验、抑制试验和B细胞辅助试验。此外，我们将确定将启动的信号通路，以诱导新生儿和儿童T细胞中IL-10的表达。此外，这些实验还提供了新生儿、婴儿和儿童的抗原特异性T细胞反应及其在CD4+T细胞中的信号通路的全面图景。此外，它还将提供对迄今尚不清楚的人类真菌感染的细胞或分子原因以及与年龄相关的差异的见解。

Adaptive immune responses of neonates, infants and children react differently than those of adults. Others and we were able to show that in fact CD4 + T cell activation and differentiation is highly age-dependent in early life stages. However, this has so far been demonstrated mainly by antigen-nonspecific polyclonal stimulation. New preliminary results now show that even antigen-specific responses - as a model, antifungal T cell responses to peptides and lysates of the fungi Candida albicans or Aspergillus fumigatus - are vigorously initiated from birth. The neonatologically responsive T cell pool consists of 20 different TCR Vβ families, while pediatric and adult pools show dramatically less variability. We could not show an age-dependent bias for IL-4 expression, but a pronounced IL-17 and IL-10 production. Remarkably, only neonatal and infant T cells showed immediate co-expression of multiple cytokines. In addition, only their naive, activated T cells co-express the transcription factors T-bet and RORγt and subsequently their target genes IL-17 and IFNγ. This indicates that neonatal and infant T cells are predetermined to respond rapidly to high fungal plasticity, which may provide a point of intervention for therapeutic interventions.In the present project, we will focus on functional and molecular aspects of age-related antigen-specific T cell activation and differentiation, using as model our well-characterized antifungal responses to Candida albicans and Aspergillus fumigatus in human T cells. First, we will extend our original work on polyclonal, antigen-unspecific T cell activation to antigen-specific, using MELC technology to analyze the T cell APC synapse. Next, we will identify neonatal-type IL-17 production and its plasticity using kinom profiling, for cytokine signalling, stat analysis, and T-cell differentiation approaches. Another goal is the functional and molecular analysis of antifungal IL-10 producers in neonates, infants, and children, which we see as a key switch to shut down T cell responses (including Th17). Differentiation tests, suppression tests and B-cell helper assays are to be carried out for this purpose. In addition, we will identify signalling pathways that will be initiated for the induction of IL-10 expression in neonatal and pediatric T cells.Together, these experiments provide a comprehensive picture of an antigen-specific T cell response of neonates, infants and children and their signalling pathways in CD4+ T cells. In addition, it will provide insights into the hitherto not understood cellular or molecular causes and age-related differences in fungal infections in humans.